The expert is Cecile Rose, MD, MPH, head of the division of environmental
and occupational health sciences at National Jewish Medical and Research Center
and associate professor of pulmonary medicine at the University of Colorado
School of Medicine.

Rose reported the case in a July 18 letter to the FDA, the CDC, the EPA, and
the Occupational Safety and Health Administration. None of these agencies has
yet issued a public health alert. The letter became public when published on
The Pump Handle web site, a public health blog.

According to her letter, the man complained of a worsening cough and
increasing shortness of breath. Lung function tests and imaging studies show he
has bronchiolitis obliterans -- obliteration of the tiny airways in the
lung.

It's a rare disease, first seen in 1985 in workers in food-flavor factories.
In 2002, the disease was seen in workers making microwave popcorn -- in
particular, those exposed to a buttery-tasting chemical called diacetyl. There
have been many other reports since then, with at least three deaths and many
patients awaiting lung transplants.

But Rose's patient had never been exposed to food-flavoring fumes. His only
exposure was to the two or more bags of microwave popcorn he consumed every
day.

Rose took a team to the man's house and tested the air while microwaving
some popcorn. Air levels of diacetyl were similar to those in the area of a
microwave popcorn factory where workers were affected.

Many foods other than popcorn contain diacetyl. There's no indication that
eating these foods is dangerous. But breathing fumes containing diacetyl
appears to be very dangerous.

Microwave popcorn, of course, gives off hot fumes if the bag is opened
before the cooked popcorn cools. According to news reports, Rose's patient
liked to inhale the aroma of newly popped microwave popcorn. Rose reports that
his symptoms stopped getting worse when he stopped making microwave
popcorn.

Federal Action Needed

David Michaels, PhD, MPH, associate chairman of the department of
environmental and occupational health at George Washington University, runs the
Pump Handle blog. A year ago, he petitioned the FDA to stop designating
diacetyl as a food "generally recognized as safe" -- that is, an
acceptable food.

"The key issue is, are there susceptible populations -- children,
asthmatics, people with existing lung disease -- who are at more risk? Are
people getting sick at lower exposure levels?" Michaels tells WebMD.
"Dr. Rose is a leading lung expert who knows that diacetyl vapors cause
lung disease. But will the average pediatrician who sees a child with what
seems to be worsening asthma be looking for microwave popcorn
exposure?"

Michaels says it's time for federal agencies to act.

In March 2005, the EPA told WebMD that a study of microwave popcorn
emissions would be completed in 2005. The study looked at some 50 different
microwave popcorn types and batches to identify and measure the compounds
emitted during the cooking process.

According to documents obtained by Michaels, the popcorn industry already
has seen the EPA study. The EPA now tells WebMD that the study has been
submitted for publication and may appear as early as next month.

Meanwhile, four of the leading makers and sellers of microwave popcorn have
acted. Con Agra, General Mills, American Pop Corn Company, and Pop Weaver have
said they will stop using diacetyl in their products, according to news
reports. Their brands include Orville Redenbacher, Act II, Pop Secret, Jolly
Time and Pop Weaver.